LAUSR

813 gene therapy, as is evident by a more stable patenting trend. The stark difference between the mAb and gene therapy ecosystems is also illustrated by the top patenting entities from 2003 to 2014 (Table 1). Whereas in gene therapy the majority of top patentees are research organizations, in mAbs the majority are biotech and pharmaceutical firms. The persistence of publicly funded research was instrumental in resolving many of the scientific challenges associated with gene therapy. Today there is renewed optimism about the promise of gene therapy to treat major diseases such as hemophilia and cancer. Gene therapy–based biotech firms raised more than $1 billion through initial public offerings in 2015 and 2016. To explore the recent resurgence in gene therapy, we examined all clinical trials during the period 2012–2016 for new therapeutics (Table 2). Because mAbs have had a relatively smooth trajectory of technological progress, there are more trials in mAbs than in gene therapy, and many of these trials are in advanced stages of clinical development. As expected from Challenges in the gene therapy commercial ecosystem